Answer :
In an overhead cam engine, push rods are not required as the camshaft directly interacts with the valves and rockers; therefore, option (d) all of the above is correct.
In an overhead cam engine, push rods are not needed to operate any of the following: (a) rockers and valves, (b) camshaft and valves, (c) camshaft and rockers, (d) all of the above. The correct answer is (d) all of the above. In this type of engine design, the camshaft is located in the cylinder head, right above the valves. This allows for a direct interaction between the camshaft and the valves through the use of rockers or directly acting cam followers. The absence of push rods reduces the engine's complexity and can improve its performance.
